1. Field of the Invention
The present invention relates to a liquid chromatograph apparatus and a liquid chromatograph analysis method.
2. Description of the Related Art
For analyses in which a liquid chromatograph apparatus is used, a plurality of components in a sample are detected by means of a gradient method which mixes a plurality of eluents and allows their concentration to change during analysis. The gradient method uses a plurality of liquid transfer devices different in liquid transfer velocity to make it possible to prepare a targeted mixing concentration on the basis of a difference between their velocities.
To improve the degree of reproducibility of analysis, JP-2012-58264-A (hereinafter referred to as Patent Document 1) discloses a technology which includes means for transmitting to an autosampler or a control unit the fact that a plurality of pumps reach the given timing of a liquid transfer cycle. In addition, the technology promotes synchronization with an analysis cycle by transmitting information on a pump whose liquid transfer cycle is slowest to the autosampler or the control unit.
JP-2006-17590-A (hereinafter referred to as Patent Document 2) describes switching from a start operation mode to a steady operation mode. In the start operation mode, one of two pumps is operated in order to reduce a rise time at the time of starting the pump. In the steady operation mode, after the discharge pressure of fluid has reached a predetermined value, the pump which has been operated is stopped and the other pump is operated.
JP-7-72130-A (hereinafter referred to as Patent Document 3) discloses determining a timing at which supply of fluid into a system is started, by monitoring a fluid compression process and detecting the system pressure being obtained precisely.
International Publication No. WO2003/079000 (hereinafter referred to as Patent Document 4) discloses a high-pressure gradient liquid transfer method, specifically, a method of controlling the rotational speed of a motor on the basis of the position of a cam for operating the motor and a differential value between pressures in a plurality of pumps.
JP-T-2008-511002 (hereinafter referred to as Patent Document 5) discloses the fact that to suppress a decrease in fluid pressure resulting from the injection of a sample, the operation of a pump is controlled before or during the injecting operation to change the pressure.